Oxygen sensor assembly for medical ventilator

ABSTRACT

The present invention relates to oxygen sensors for medical ventilators. A medical ventilator includes a patient circuit delivering inspiratory airflow to a patient and returning expiratory airflow from the patient back to the ventilator. A manifold includes an air flow path into the patient circuit, and a port with an opening for an oxygen sensor. When mated to the port, the oxygen sensor samples the air in the air flow path and detects the amount of oxygen in the air. When the oxygen sensor is inserted into the port, a valve is biased open, to allow airflow through the opening into the oxygen sensor during ventilation. When the oxygen sensor is removed from the port, the valve biases into a closed position covering the opening, to prevent leaks. The ventilator can then continue to operate without the oxygen sensor in place.

FIELD

The present invention relates to oxygen sensors for medical ventilators.

BACKGROUND

Medical ventilators can provide life-sustaining oxygen delivery tocritically ill patients who may otherwise be unable to breathesufficiently. Ventilators can mix oxygen with room air to achieve adesired percentage of oxygen in the air delivered to the patient. Someventilators include an oxygen sensor that samples the flow of air beingdelivered to the patient and detects the amount of oxygen in thedelivered air. The information from the oxygen sensor enables theventilator to check that the oxygen delivery system is workingappropriately, to confirm that the appropriate oxygen percentage ismaintained, and/or to make adjustments if necessary.

The oxygen sensor may need to be periodically removed from theventilator in order to be cleaned or replaced. In some cases, theventilator is removed from service so that the oxygen sensor can bereplaced while the ventilator is not operating on a patient.

SUMMARY

A medical ventilator includes a patient circuit delivering inspiratoryairflow to a patient and returning expiratory airflow from the patientback to the ventilator. A manifold includes an air flow path into thepatient circuit, and a port with an opening for an oxygen sensor. Whenmated to the port, the oxygen sensor samples the air in the air flowpath and detects the amount of oxygen in the air. When the oxygen sensoris inserted into the port, a valve is biased open, to allow airflowthrough the opening into the oxygen sensor during ventilation. When theoxygen sensor is removed from the port, the valve biases into a closedposition covering the opening, to prevent leaks. The ventilator can thencontinue to operate without the oxygen sensor in place.

In an embodiment, a medical ventilator includes a manifold with a firstair flow path to a patient circuit. The ventilator also includes a portin the manifold. The port has a second air flow path through an openingin the port. The first and second air flow paths are in fluidcommunication with each other, and the port is configured to mate withan oxygen sensor assembly. The ventilator also includes a valve biasedtoward a closed position in which the valve closes the opening. Thevalve is movable, by insertion of the oxygen sensor assembly, into anopen position in which the second air flow path through the opening isexposed.

In an embodiment, a method for replacing an oxygen sensor on a medicalventilator includes mating an oxygen sensor assembly to a port of amedical ventilator. The oxygen sensor assembly has an oxygen sensor, andthe port includes a valve biased to close the port. The method alsoincludes operating the medical ventilator with the oxygen sensor, andremoving the oxygen sensor assembly from the port. Mating the oxygensensor assembly to the port includes automatically opening the valve,and removing the oxygen sensor assembly from the port includesautomatically closing the valve.

In an embodiment, an oxygen sensor assembly for a medical ventilatorincludes an adapter with a surface that interfaces with the medicalventilator to open a valve to allow airflow from the medical ventilatorto the oxygen sensor. Optionally, the adapter includes a body and alatch. The body includes a cavity for receiving an oxygen sensor, andthe latch is movable to retain the oxygen sensor assembly to theventilator. The body includes either a groove or a projection, and thelatch includes the other of the groove or the projection, such that thegroove and the projection mate to secure the latch to the body. In anembodiment, the oxygen sensor assembly also includes an oxygen sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic view of a medical ventilator interactingwith a human patient, according to an embodiment of the presentdisclosure.

FIG. 2 illustrates a cross-sectional view of an oxygen sensor assemblymated to a port of a medical ventilator, according to an embodiment ofthe present disclosure.

FIGS. 3A-B illustrate side views of an oxygen sensor assembly in openand closed positions, respectively, according to an embodiment of thepresent disclosure.

FIGS. 4A-C illustrate cross-sectional views of the oxygen sensorassembly and port of FIG. 2, in stages of insertion and removal.

FIG. 5 illustrates a method for installing and removing an oxygen sensoron a ventilator, according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

The present invention relates to oxygen sensors for medical ventilators.In an embodiment, a medical ventilator includes a valve that closes whenthe oxygen sensor is removed from the ventilator, to allow theventilator to continue to operate without air flow leaks when the oxygensensor is removed.

In an embodiment, a medical ventilator includes a patient circuitdelivering inspiratory airflow to a patient and returning expiratoryairflow from the patient back to the ventilator. A manifold includes anair flow path into the patient circuit, and a port with an opening foran oxygen sensor. When mated to the port, the oxygen sensor samples theair in the air flow path and detects the amount of oxygen in the air.When the oxygen sensor is inserted into the port, a valve is biasedopen, to allow airflow through the opening into the oxygen sensor duringventilation. When the oxygen sensor is removed from the port, the valvebiases into a closed position covering the opening, to prevent leaks.The ventilator can then continue to operate without the oxygen sensor inplace. The valve may be positioned to open automatically when the sensoris mated to the port, and to close automatically when the sensor isremoved. In an embodiment, the oxygen sensor is received into an adapterthat is configured to interact with the valve to open the valve when theoxygen sensor is mated to the port. In an embodiment, the oxygen sensorand the adapter are integrated together.

FIG. 1 shows a schematic view of a ventilator 100 providing ventilationto a human patient 10, according to an embodiment. The ventilator 100includes a pneumatic system 102 coupled to a patient circuit 130 thatprovides airflow between the ventilator and the patient. In anembodiment, the patient circuit 130 includes a set of tubes that connectat one end to the ventilator and at the other end to a patient interface138. The patient interface 138 includes suitable tubing and seals forinsertion into a patient's airway, or for use around the patient's noseand mouth. In an embodiment, the patient circuit 130 includes aninspiratory limb 132, delivering airflow from the ventilator to thepatient, and an expiratory limb 134, delivering exhaled airflow from thepatient to the ventilator. The two limbs may be joined at a wye fitting136, leading to the patient interface 138. Airflow into the patientcircuit 130 is controlled by the pneumatic system 102. Specifically, thepneumatic system includes an inspiratory valve 104 that controls airflowinto the inspiratory limb 132, and an expiratory valve 108 that controlsairflow exiting the expiratory limb 134.

In an embodiment, the pneumatic system 102 also includes a compressor106, one or more sensors 107, such as pressure sensors, flow sensors,temperature sensors, gas sensors, and/or other sensors, and variousvalves, fittings, and conduits routing air flow to and from theinspiratory and expiratory valves. In some embodiments, the pneumaticsystem 102 includes pressure-regulating valves 103 and 105 that controlpressurized air and oxygen sources 117 and 118, respectively. Thepressurized air and oxygen sources may be available from wall outlets(in modern medical facilities) or from tanks. These air sources arerepresented as tanks in FIG. 1, but may be wall outlets or othersources. These pressure regulating valves (or regulators) 103 and 105control the release of air and oxygen from these wall outlets or tanks.Each regulating valve regulates flow from its tank so that the combinedrespiratory gas delivered to the patient has a desired concentration ofoxygen and is supplied to the patient at desired pressures and rates. Inthis context, an oxygen sensor is often included in order to sample theairflow to the patient and confirm that the appropriate oxygenconcentration is being delivered.

Still referring to FIG. 1, the ventilator 100 also includes a userinterface 120 including a display screen 122. In an embodiment, thedisplay screen 122 is a touch screen that receives user inputs and adisplay that displays information. For example, the display 122 enablesa user to view current patient parameters, change pressure and flowsettings, adjust alarm limits, view historical data, and pause audiblealarms, among other functions.

Still referring to FIG. 1, the ventilator 100 also includes a controller110 that includes a processor 116, memory 112 such as random accessmemory (RAM), data storage 114, and/or other components commonly foundin computing devices. The memory 112 may include non-transitory,computer-readable storage media that stores software that is executed bythe processor 116 and which controls the operation of the ventilator100. In an embodiment, the memory 112 includes one or more solid-statestorage devices such as flash memory chips. In an alternativeembodiment, the memory 112 may be mass storage connected to theprocessor 116 through a mass storage controller (not shown) and acommunications bus (not shown). Although the description ofcomputer-readable media contained herein refers to a solid-statestorage, it should be appreciated by those skilled in the art thatcomputer-readable storage media can be any available media that can beaccessed by the processor 116. That is, computer-readable storage mediaincludes non-transitory, volatile and non-volatile, removable andnon-removable media implemented in any method or technology for storageof information such as computer-readable instructions, data structures,program modules or other data. For example, computer-readable storagemedia includes RAM, ROM, EPROM, EEPROM, flash memory or other solidstate memory technology, CD-ROM, DVD, or other optical storage, magneticcassettes, magnetic tape, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to store thedesired information and which can be accessed by the computer.

In an embodiment, the controller 110 also includes a trigger module 115,which triggers inspiration according to ventilator settings, such asthose prescribed by a clinician. In an embodiment, the trigger module115 triggers an inspiration based on expiration of a determined amountof time (for the patient to exhale), or based on detection of a triggercondition (such as patient effort to breathe). In response to a triggerfrom the trigger module, the control system sends control signals to thepneumatic system 102 to operate the inspiratory and expiratory valves todeliver air to the patient.

FIG. 2 shows an oxygen sensor assembly 210 mated to a ventilatormanifold 212, according to an embodiment of the invention. The manifold212 includes a first air flow path 214 that conveys air flow to thepatient circuit 130 (shown in FIG. 1). This air flow path 214 isdownstream of the pressure regulating valves 103 and 105 (shown in FIG.1), and includes mixed air and oxygen that will be delivered to thepatient for breathing. The manifold 212 also includes a port 216 thatmates with the oxygen sensor assembly 210. The port 216 includes asecond air flow path 220 through an opening 218 in the port 216. Thisopening 218 allows air to flow through the port and into the oxygensensor assembly, where the oxygen content of the air is measured. Thetwo air flow paths 214 and 220 are in fluid communication with eachother, such that same air flow that is delivered to the patient issampled by the oxygen sensor.

The oxygen sensor assembly 210 includes an oxygen sensor 222 retained bya sensor adapter 224. The adapter 224 will be described in more detailbelow with reference to FIG. 4. The oxygen sensor 222 itself is a sensorthat can measure the concentration of oxygen in a sample of air. Theoxygen sensor may be a chemical sensor such as a galvanometric oxygensensor. As another alternative, the oxygen sensor may be a magneticsensor that operates based on the magnetic properties of oxygen. Othertypes of oxygen sensors that measure the concentration (such as apercentage) of oxygen within a sample or flow of air may be suitable foruse with the ventilator 100.

Referring again to FIG. 2, a sensor shutoff valve 226 is positioned tointeract with the port 216 to open and close the port when the oxygensensor is inserted and removed from the port. The oxygen sensor assembly210 interacts with the valve to open the valve when the oxygen sensorassembly is inserted into the port, and maintain the valve open whilethe oxygen sensor assembly is mated to the port. A biasing element oractuator operates to automatically close the valve when the oxygensensor is removed from the port. In FIG. 2, the valve is shown in theopen position. In the open position, the opening 218 is exposed to theair flow path 220, and thereby allowing air to flow through the opening218 into the oxygen sensor 222.

The valve 226 that is shown in FIG. 2 will be described in more detail,though it will be understood that other types of valves may be suitableas well. In FIG. 2, the valve 226 includes a spring-biased valve with amovable plunger 228. The plunger 228 translates through the opening 218,toward and away from the manifold. In the embodiment shown, the biasingelement or actuator includes a spring 234 that is trapped between anoutward face 236 of the manifold and a retainer 238. The retainer 238 isretained to the plunger 228 by a suitable fastener which may be aseparate piece, or integrated with the retainer. The retainer itselfincludes openings, passages, or perforations that allow passage of airflow through the retainer into the oxygen sensor. When the valve isopen, the spring is compressed between the outward face 236 and theretainer 238, and the plunger 228 is translated into the manifold, awayfrom the oxygen sensor 222. The shaft of the plunger includes across-sectional area that is smaller than the opening 218, therebyexposing a passage 240 between the plunger and the edges of the opening218. When the oxygen sensor is removed, the spring expands, moving theplunger away from the manifold and toward the former position of theoxygen sensor, until a foot 230 at the end of the plunger reaches aseating surface 242 of the manifold. The foot 230 is larger than theopening 218. When the foot 230 is seated against the seating surface242, the foot covers the opening, closing the air flow path 220. Thefoot may include a gasket or seal 232, such as an o-ring, to prevent airfrom leaking out of the manifold between the foot and the seatingsurface 242. Additionally, the spring urges the foot against the seatingsurface to contribute to a tight seal.

When the oxygen sensor assembly is inserted again into the port 216, afront face 244 of the sensor adapter 224 makes contact with the retainerand pushes the retainer toward the manifold. This movement compressesthe spring 234 and moves the foot 230 away from the seating surface 242,thereby exposing the passage 240 through the opening 218. A portion ofthe air flowing through the first flow path 214 to the patient interfaceflows through the passage into the oxygen sensor for measurement. WhileFIG. 2 shows the front face 244 of the sensor adapter 224 making thiscontact, in other embodiments, the oxygen sensor 222 itself can interactwith the valve to open the valve, without the use of a sensor adapter.For example, the oxygen sensor may be push-fit, snapped, threaded, orotherwise mated directly into the port 216, without a sensor adapterbetween the sensor and the port. In this case, a front face or otherfeature on the oxygen sensor itself can contact the valve 226 to openthe valve when the sensor is inserted into the port, or the oxygensensor can trigger an actuator that opens the valve, as describedfurther below.

Two perspective views of the oxygen sensor assembly 210 are shown inFIGS. 3A and 3B, to illustrate the latching features of the adapter 224.The adapter 224 includes a body 248 that forms a cavity 250 thatreceives the front end of the oxygen sensor 222. In an embodiment, theoxygen sensor includes threads that mate with threads inside the cavity250 (see threads 278 in FIGS. 2 and 4A-C) to retain the oxygen sensor tothe adapter. These threads are optional; in other cases, the oxygensensor may be retained to the adapter by a slip or friction fit, or by alatch such as the latch 254 (described more below). The adapter 224includes a plug 252 at a first end of the adapter, and a latch 254 at asecond, opposite end. The plug 252 contacts the valve in the manifold toopen the valve when the sensor assembly is inserted into the ventilator(as described with reference to FIG. 2). The plug 252 also includes aseal 256 such as a gasket or o-ring that contacts a sealing surface 258of the port 216 (see FIG. 2) to prevent air from leaking out of theventilator between the manifold and the sensor assembly when the sensorassembly is mated to the port. The spring 234 can be chosen such that itis not strong enough to push the oxygen sensor assembly out of the portagainst the friction of the o-ring 256. In another embodiment, the plug252 includes threads (not shown) that engage mating threads on the portto secure the adapter to the port, or other mechanical mating features.

The latch 254 rotates about a hinge 260 between open and closedpositions. In an embodiment, the latch 254 rotates freely, without beingbiased or urged into either position. The latch includes a foot 264opposite the hinge 260. The foot includes a detent or projection 262that engages a matching groove 266 on the adapter opposite the hinge. InFIG. 3A, the latch is shown rotated outwardly away from the groove orindentation 266, toward the open position in which the oxygen sensor 222can be slid out from the cavity 250 and removed from the adapter 224. InFIG. 3B, the latch is rotated toward the adapter, and the detent 262 ismated with the groove 266. The engagement of the detent with the groovesecures the latch in place behind the oxygen sensor, opposite the plug252. It should be noted that the figures show a detent 262 on the latchand a groove 266 on the adapter, but these may be reversed, or othersuitable mating features may be used.

The latch 254 also includes a grip 268 opposite the hinge 260. To removethe oxygen sensor from the sensor adapter, a user can push against thegrip 268, which will cause the latch detent 262 to disengage from thegroove 266 as the latch rotates about the hinge 260, as described morefully below with references to FIGS. 4A-C.

FIGS. 4A-C show the oxygen sensor assembly 210 in three stages ofinsertion/removal from the ventilator manifold 212. In FIG. 4A, theoxygen sensor assembly 210 is fully mated to the port 216, and thesecond air flow path 220 through the passage 240 into the oxygen sensor222 is open. The spring 234 of the valve is compressed, and the foot 230of the plunger 228 is pushed away from the opening 218. The latch 254 ofthe sensor adapter is in the closed position, with the detent 262engaging the groove 266. As described below and with reference to theseFigures, the latch 254 assists in retaining the oxygen sensor assemblyto the ventilator port.

Additionally, in the embodiment shown, the manifold 212 includes a clipor trap 270 that engages a wing 272 of the latch 254. The wing 272rotates about the hinge 260 with the latch 254. When the oxygen sensoris fully mated to the port 216, the latch 254 is closed, and the wing272 is seated in the clip 270. The clip 270 holds the latch in place,preventing the spring 234 of the valve from pushing the oxygen sensorout away from the port 216. Optionally, an additional rear door (notshown) can be closed behind the latch, further securing the oxygensensor into the port. Such a door also confirms to the user that theoxygen sensor has been installed to the correct depth in the port, asthe door can be positioned such that it cannot close if the oxygensensor is not fully seated into the port.

FIG. 4B shows the oxygen sensor assembly in a first stage of releasefrom the port 216. To release the oxygen sensor from the port, the latchis rotated outwardly away from the manifold. The user pushes the grip268 to release the detent 262 from the groove 266 and free the latch torotate. As the latch rotates about the hinge 260, the wing 272 rotatesdown and out of the clip 270. As the latch further rotates, an endsurface 274 of the latch abuts an end surface 276 of the clip 270. Thecontact between these two surfaces prevents the end surface 274 fromfurther rotating with respect to the hinge. As a result, as the usercontinues to pull on the grip 268 to rotate the latch, the sensoradapter slides out from the port 216. The latch acts as a lever, withthe end surface 274 pressing against the clip end surface 276 to provideleverage to move the sensor out of the port. The asymmetry of the latchabout the hinge 260 forms a lever arm that translates a smaller forceapplied by the user about the hinge into a larger force applied againstthe surface 276. This leverage can be useful in case the seal or o-ring256 on the sensor adapter sticks to the manifold, which can happen overtime.

In an embodiment, a small amount of force applied by the user to thegrip 268, such as 2 pounds, is translated by the latch into a largerresulting amount of force, such as 10 pounds, applied by the end surface274 of the latch against surface 276 of the clip 270. In an embodiment,the lever arm amplification is about 3:1, or 4:1, or 5:1. In anembodiment, the force required to push the latch 254 closed (pushing thedetent 262 into the groove 266) is about 2 pounds.

The interaction of the wing 272 and clip 270 also assists the user inpositioning the oxygen sensor assembly 210 to the correct depth withinthe port 216, and gives a tactile feedback indicating that the oxygensensor has been correctly installed. The engagement of the detent 262into the groove 266 also provides a tactile and optionally audible“click” that confirms that the latch is in the proper position.

As the sensor assembly 210 moves away from the port 216, the valve 226automatically moves into the closed position. As shown in FIG. 4B, thespring 234 expands, pushing against the retainer 238 and causing theplunger 228 to move outwardly away from the manifold, toward the oxygensensor, until the foot 230 of the plunger rests against the seatingsurface 242.

FIG. 4C shows the oxygen sensor assembly 210 fully removed from the port216, and the valve 226 fully closed. In this position, the foot of theplunger of the valve provides a seal against the seating surface of themanifold, preventing airflow from escaping through the opening 218.Airflow continues through the first air flow path 214 to the patientcircuit, without loss of air through the oxygen sensor port 216. Theoxygen sensor 222 may be removed from the adapter and either cleaned ordiscarded, and a new or cleaned sensor may be replaced.

As shown in FIGS. 4B and 4C, in an embodiment, the valve 226automatically opens when the oxygen sensor is inserted, andautomatically closes when the oxygen sensor is removed. The user cansimply press the grip 268 to remove the oxygen sensor assembly 210,without introducing a large leak into the patient breath circuit throughthe opening 218. The valve is automatically biased to close the opening218 when the oxygen sensor is removed, so that the port 216 is sealed.The ventilator can then continue to provide accurate breaths toventilate the patient, albeit without the confirming measurement ofoxygen concentration provided by the oxygen sensor. If the oxygen sensoris simply being quickly cleaned and/or replaced, the ventilator cancontinue to operate safely without the oxygen sensor for a short periodof time. Then the new and/or cleaned oxygen sensor can be inserted intothe port 216 when ready, and the oxygen sensor can again providemeasurements of oxygen concentration to verify that the correctconcentration is being provided to the patient. Throughout this process,the ventilator does not need to be taken out of service, and the patientdoes not need to be moved to a new ventilator in order to remove orreplace the oxygen sensor. Additionally, the interactions of the latchand the manifold make it easy for the user to confirm that the oxygensensor is fully mated to the port.

In an embodiment, a ventilator such as ventilator 100 (shown in FIG. 1)includes a user interface such as user interface 120 that interacts withthe user regarding the presence, function, and/or removal of the oxygensensor. In an embodiment, the ventilator includes a sensor or switchthat detects when the oxygen sensor is not connected to the port 216.The switch can be a physical switch contacted by the oxygen sensor (orsensor assembly), an optical gate blocked by the oxygen sensor, anelectrical contact made by the oxygen sensor, a position sensor thatdetects opening of a component such as the latch or access door behindthe oxygen sensor, a magnetic sensor, or any other suitable switch orsensor. This switch may inform the ventilator that the oxygen sensor isremoved or about to be removed, or that it is not properly or fullyseated in the port. In an embodiment, such a switch may trigger anactuator that operates the valve. In this case, insertion of the sensor(or sensor assembly) activates the switch, when then triggers theactuator to open the valve, and removal of the sensor similarly triggersthe actuator to close the valve. In this way, insertion and removal ofthe oxygen sensor can control the valve without requiring physicalcontact between the sensor and the valve.

When the ventilator detects that the oxygen sensor is not installed, theventilator displays a warning and/or notification through the display122 of the user interface 120. The warning may include visual and/oraudible alerts, such as a written message, flashing colors, and audiblesounds. The user interface 120 also includes an input (such as atouchscreen, interactive menu, buttons, keys, etc.) that enables theuser to disable these alarms or warnings, or put them on a temporarypause. The user can then replace or clean the oxygen sensor while theventilator continues to ventilate the patient. In an embodiment, theuser interface includes an input or menu or other mechanism for the userto inform the ventilator, prior to removing the oxygen sensor, that theuser is about to remove the oxygen sensor for replacement or cleaning.The user inputs this information through the user interface, and thenthe ventilator enters a mode of operation in which it does not rely onor attempt to use the measurement from the oxygen sensor. In this mode,when the user removes the oxygen sensor, the ventilator does not producean alarm. The ventilator may still provide a written warning or messageor other display that indicates that it is operating without an oxygensensor.

FIG. 5 illustrates a method 300 for replacing an oxygen sensor in amedical ventilator, according to an embodiment of the presentdisclosure. The method includes connecting an oxygen sensor with anadapter, at 301. The combined components form the oxygen sensor assembly(such as assembly 210 in FIG. 2). This first step is omitted where theoxygen sensor and adapter are integrated together in one piece. Themethod 300 includes mating the oxygen sensor assembly to the ventilatorport, at 302. In an embodiment, mating the oxygen sensor assembly to theport includes sliding, pushing, or threading the assembly into the port,forming a seal between the assembly and the port, and engaging the valve(such as valve 226 in previous figures) to open the valve, as describedin further detail above. In an embodiment, this step also includeselectrically connecting the oxygen sensor to the ventilator. The oxygensensor may include a separate wired electrical connector that plugs intoa corresponding electrical port on the ventilator, to enable the oxygensensor and ventilator to communicate. After mating the oxygen sensorassembly to the port, the method includes securing the adapter latch at303. The latch retains the sensor assembly to the port and confirms thatthe sensor assembly has been installed to the correct depth. In anembodiment, the latch is secured after the oxygen sensor assembly isinserted into the port, so that the latch can engage the ventilator(such as the clip 270) when the latch is secured. With the oxygen sensorinstalled, the method includes operating the ventilator with the oxygensensor, at 304. The ventilator may continue to operate with the oxygensensor for several months without any need to remove, replace, orinspect the sensor. When functioning properly, the oxygen sensor samplesthe air flowing to the patient circuit, measures the oxygenconcentration in the air, and provides that measurement to theventilator (such as to the processor 116) so the ventilator can confirmthat the desired concentration is being provided.

At some point, the oxygen sensor may become exhausted, clogged, orbroken. A user may replace or clean the sensor on a set schedule, suchas every few months, or may wait for the ventilator to indicate that thesensor is not functioning correctly. The method 300 optionally includesdisabling a function on the ventilator relating to the oxygen sensor,such as an alarm, warning message, or oxygen sensor functionality, at305. The user may accomplish this through the user interface. This stepis optional. The method 300 includes removing the oxygen sensor assemblyby first releasing the latch at 306, and then using the latch to removethe oxygen sensor assembly from the port, at 307. This may be done asdescribed above with references to FIGS. 4A-C. When the oxygen sensorassembly is removed, the ventilator may activate an alarm or warning, ifnot earlier paused or disabled. The method includes pausing or disablingthe ventilator alarm at 308. This is optional, and may not be relevantif the ventilator does not activate an alarm. The method includesremoving the oxygen sensor from the sensor adapter, at 309, if the twocomponents are separate. Optionally, the method includes cleaning orreplacing the oxygen sensor at 310, and from there the method may berepeated.

The method outlined in FIG. 5 may vary in other embodiments. Forexample, in some embodiments, the oxygen sensor itself can be directlyinserted into the ventilator to interact with the port and the portvalve, without a sensor adapter. As another example, the valve may beoperated independently of the sensor or sensor assembly, such that thevalve is separately actuated into an open or closed position,independently of removal or insertion of the valve. In this case, thevalve is not automatically opened or closed when the sensor or sensorassembly is inserted or removed, but can be separately opened or closedvia its own actuator or switch. An oxygen sensor can be inserted, thenthe valve opened, and later the valve can be closed, and then the sensorremoved.

Though a spring-biased plunger valve is shown in the figures, it shouldbe understood that other types of valves may be suitable for closing theoxygen sensor port, in other embodiments. For example, other suitablevalves include flapper valves, duck valves, umbrella valves, gatevalves, and butterfly valves. In other embodiments, the valve may beoperated by a user, such as by a turn handle, or by a solenoid or otheractuator. An actuator can be operated by a user, or automaticallyactivated by a switch or sensor that is triggered when the oxygen sensoris removed.

Additionally, while the oxygen sensor 222 and the sensor adapter 224 areshown in the figures as separate components, in another embodiment, thetwo are integrated together into one piece. The housing of the adaptermay include the features that interact with the port 216, such as a seal256, front face 244, and wing 272. The sensor itself can then beinserted into the port, with the front face of the sensor contacting thevalve to open it, and the seal contacting the port to prevent leaks. Thewing, or a similar feature formed on the sensor body itself, caninteract with the clip 270 to retain the sensor to the port. A movablelatch such as latch 254 may be integrated with the body or housing ofthe sensor itself. In such an embodiment, the sensor is not removed froma separate adapter housing, and there is no need to provide anengagement or seal (such as threads) between the sensor and adapter.

Although the present invention has been described and illustrated inrespect to exemplary embodiments, it is to be understood that it is notto be so limited, since changes and modifications may be made thereinwhich are within the full intended scope of this invention ashereinafter claimed.

1.-11. (canceled)
 12. A method for replacing an oxygen sensor on amedical ventilator, comprising: mating an oxygen sensor assembly to aport of a medical ventilator, the oxygen sensor assembly comprising anoxygen sensor, and the port comprising a valve biased to close the port;operating the medical ventilator with the oxygen sensor; and removingthe oxygen sensor assembly from the port, wherein mating the oxygensensor assembly to the port comprises opening the valve, and whereinremoving the oxygen sensor assembly from the port comprises closing thevalve.
 13. The method of claim 12, further comprising securing theoxygen sensor assembly to the port with a latch.
 14. The method of claim12, further comprising disabling a setting of the medical ventilatorrelating to the oxygen sensor prior to removing the oxygen sensorassembly from the port.
 15. The method of claim 12, further comprisingpausing an alarm or alert after removing the oxygen sensor assembly fromthe port.
 16. The method of claim 12, wherein mating the oxygen sensorassembly to the port comprises automatically opening the valve, andwherein removing the oxygen sensor assembly from the port comprisesautomatically closing the valve.
 17. The method of claim 16, whereinmating the oxygen sensor assembly to the port comprises making physicalcontact between the oxygen sensor assembly and the valve to open thevalve.
 18. The method of claim 16, wherein mating the oxygen sensorassembly to the port comprises triggering an actuator that opens thevalve. 19.-20. (canceled)